The present invention relates to the sector of aircraft engine assemblies comprising an engine, an engine mounting pylon and means for mounting the engine on a primary structure of the mounting pylon.
The invention also relates to an aircraft equipped with such an engine assembly. It is applicable preferably to commercial aircraft.
In existing aircraft, engines such as turbojet engines are suspended underneath the wing by complex mounting devices, also called “EMS” (engine mounting structures), or also mounting pylons. The mounting devices usually employed have a rigid structure, called a primary structure. This primary structure forms a box, namely, it is formed by the assembly of lower and upper spars joined together by a plurality of transverse stiffening ribs situated inside the box. The spars are arranged along top and bottom faces, while side panels close the box along side faces.
In a known manner, the primary structure of these pylons is designed to allow the transmission, to the wing, of the static and dynamic loads generated by the engines, such as the weight, the thrust or the different dynamic loads.
In the known solutions of the prior art, the transmission of the loads between the engine and the primary structure is conventionally ensured by mounting means comprising a front engine attachment, a rear engine attachment and a device for transmission of the thrust loads. A conventional example of construction of the rear engine attachment is shown in FIG. 1.
This rear engine attachment 7a connects the exhaust casing of the engine to the primary structure 6 of the mounting which is in the form of a box. For this purpose, the attachment 7a comprises a body 100 as well as a plurality of shackles 102 hinged on the engine attachment body and on the exhaust casing. More precisely, the body 100 comprises two tiers of beams stacked in the vertical direction. These comprise one or more upper beams 104, fixed by means of bolts onto the outer face of the lower spar closing the box 6, and one or more lower beams 106, fixed by means of bolts to the upper beams 104. It is this lower beam which carries, in a hinged manner, the shackles 102. More commonly, the upper beams are called “intermediate fittings,” while generally a single lower beam, more commonly called “engine beam,” is generally employed. It is pointed out that, during disassembly of the engine, for example in order to carry out maintenance operations, separation is performed in the region of the interface—indicated by 108—situated between the upper beams which remain fixed to the box 6, and the lower beam which remains fixed to the engine via the shackles 102.
Although this solution has proved to be satisfactory in many respects, there is still room for improvement. In particular, there exists the need to reduce its overall mass and/or to improve the transfer of loads between the engine and the primary structure of the mounting pylon.